Drill/countersink assembly and method for producing countersunk holes

ABSTRACT

A countersink cutter or assembly for countersinking to precise depths in various applications, including aerospace applications, uses a pneumatically driven pistol grip motor attached to a countersink tool assembly. The countersink tool assembly, which has a multi-fluted cutter, is coupled to and is coaxial with the spindle. The cutter can be preset to a precise depth at the back end of assembly through the slot using a gage.

This application claims priority on U.S. provisional patent applicationNo. 61/378,127, which was filed on Aug. 30, 2010, which is incorporatedby reference.

BACKGROUND

A countersink operation may be accomplished using microstops that mayneed frequent adjustment. In some processes, cylindrical holes aredrilled in to a substrate, e.g. non-metallic material, like composite ormetallic material, like aluminum and titanium and then countersinking ahole using a countersink tool secured in microstop. During thiscountersink operation, the pilot of the countersink (that has a frustoconical shaped cutting member with cutting edges), is inserted in tohole and motor is turned on. The microstop can require multipleadjustments as the tool is used over time. There have been many toolsdeveloped for specific needs that are very sophisticated and usehydraulics, pneumatics and electronics, etc. Such tools may be generallycumbersome and heavy.

Usually, the inspection of holes is done on test panels placed on workbenches near production area. This adjustment and checking ofcountersink depth several times before starting on production panelsrequires manpower and time. The depth of countersunk hole should bechecked after every few holes during production to ensure moreconsistent countersink depth. When the cutter is replaced, the positionof cutting edge is usually not as the same position in relation to thefront surface of the microstop and hence further adjustments of themicrostop may be necessary.

Accordingly, there is always a need for an improved countersink device,assembly and method. It is to these needs, among others, that thisdisclosure is directed.

SUMMARY

This disclosure includes a countersink assembly adapted to be attachedto a drill motor for drilling and countersinking a hole in a workpiece.The assembly has (a) an approximately cylindrical rear subassemblyextending between a first end and a second opposed end and (b) anapproximately cylindrical front subassembly having a main body, aspindle with a spindle shaft. The subassembly moves laterally inrelation to the rear subassembly. An approximately cylindricalcountersink cutter, operably connected to the drill motor, has a coaxialspindle having a bore to accommodate cutter shaft, a nose piece, andcutting edges.

Another embodiment includes a method for adjusting a countersinkassembly which includes:

-   -   a) providing a countersink assembly adapted to be attached to a        drill motor for drilling and countersinking a hole in a work        piece,    -   b) setting the front subassembly at a desired distance from the        rear subassembly; and    -   c) locking the front assembly in place with a gage.

Certain embodiments provide a method for quickly dismantling the frontportion of the front subassembly to expose the cutter for quickreplacement. The front subassembly can be dismantled very convenientlyto replace the cutter. This feature can be achieved by guiding the mainbody into the guide plate and rear subassembly and “clocking” both partssuch that they are secured by spring pressure from three (3) ballplungers at about 120 the contact surfaces of degree apart in the mainbody which creates uniform spring pressure between the main body andnose piece. This can be achieved by other means such as designing partsto accommodate magnets in both adjacent parts and providing means ofalignment or by simply using screws to fasten the two parts or by usingthe principles of cam action.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows one embodiment of the assembly of the power tool consistingof the front and rear subassemblies along with a cutter and a vacuumhose.

FIG. 2 shows an exploded view of the complete assembly shown in FIG. 1of the countersink power tool consisting front (moveable) and rear(stationary) subassemblies.

FIG. 3 shows an exploded view of the rear subassembly with, shown inFIG. 1, power tool, shown in FIG. 1, with three jaw chucks, an adaptersleeve, an adapter and a vacuum sleeve without a vacuum bag.

FIG. 4 shows an exploded view of the front subassembly consisting of amain body, a guide plate, a nose piece, spindle with cutter and thedetails inside the adapter along with vacuum hose.

FIG. 5A shows one embodiment of the assembly having a cutter and aspindle.

FIG. 5B shows a detailed view of the cutter.

FIG. 5C shows a more detailed view of the countersink cutter and spindleas assembled.

DETAILED DESCRIPTION

This disclosure is directed towards a countersink cutter, countersinkassembly and method for countersinking that can be used to cut holes toprecise depths in various applications, including aerospaceapplications, using a pneumatically driven pistol grip motor attached toa countersink tool. The countersink tool assembly, which has amulti-fluted cutter, can be coupled to and is coaxial with the spindle.The cutter can be preset to a precise depth at the back end of assemblythrough the slot using a gage. The setting of the tool can remainrelatively constant even when a cutter is replaced by another new cutteror another cutter. In addition, the cutter has a quick change mechanismin which the shaft of the cutter is coupled to the spindle coaxiallythrough cam action provided inside concentrically where the cutter issecured to the spindle and drives it. Similar rotary tools such asdrills, screw drivers, counterbores and the like are rendered useablewith the adapting mechanism and providing concentricity and torquebecause of cam action provided by the spindle and the cutter shaftsurfaces. This principle of setting up the depth from the back end oftool and quick change concept of assembly tool for cutter replacement;and quick change features of the cutter and spindle engagement includingtools other than countersink cutter replacement can be very convenientlyadapted to pneumatically driven right angle power tools and stationarymachines and other machines where the machine has movable spindle heads.

One embodiment includes a countersink assembly adapted to be attached toa drill motor for drilling and countersinking a hole in a workpiece. Asshown in FIG. 1, the assembly has an approximately cylindrical rearsubassembly (stationary) extending between a first end and a secondopposed end and having a slot for a gage. The outer diameter of theassembly defines an approximate cylinder. The rear subassembly ismounted on the drill motor with an adaptor sleeve; The assembly also hasa approximately cylindrical front subassembly having a main body, aspindle with a spindle shaft. The subassembly moves laterally inrelation to the rear subassembly. An approximately cylindricalcountersink cutter, operably connected to the drill motor, having acoaxial spindle having a bore to accommodate cutter shaft, a nose piece,and having cutting edges. The spindle shaft mounts into the drill motor.The cutter shaft has a flat front end and a flat back end along alongitudinal axis, an angular flat surface, and the groove accommodatesan O-ring. The front end of the cutter shaft coincides with the back endof body diameter of the cutter. The angular flat surface locks into apin of the spindle; and the intersection of the longitudinal axis andthe cutting edges, when projected on to the longitudinal axis, is heldin alignment at a substantially constant distance from the back surfaceof the cutter. The distance between the spindle and the nose piece areconstant and equal to the distance between the back flat surface and thecenter of the radius between the tangent of pilot diameter and thecutting edges.

Another embodiment includes a method for adjusting a countersinkassembly which includes:

-   -   d) providing a countersink assembly adapted to be attached to a        drill motor for drilling and countersinking a hole in a work        piece;    -   e) setting the front subassembly at a desired distance from the        rear subassembly; and    -   f) locking the front assembly in place with the gage.

Certain embodiments provide a method for quickly changing dismantlingthe front portion of the front subassembly to expose the cutter forreplacement. The front subassembly can be dismantled conveniently toreplace the cutter. This has been achieved, in part, by guiding the mainbody into the guide plate and nose piece subassembly and “clocking” bothparts in such a way that they get secured by the spring pressured threeball plungers at about 120 degree apart in the main body, which createsuniform spring pressure between the main body and nose piece contactsurfaces. This can be achieved by other means such as designing parts toaccommodate magnets in both adjacent parts and providing means ofalignment or by simply using screws to fasten the two parts or by usingthe principles of cam action.

Main Assembly

Referring to FIG. 2, the rear subassembly consists of a pistol gripmotor 101 (or spindle motor 101) has a Jacob chuck 202 secured to it.This chuck can also be substituted by some colleting arrangement forsecuring the spindle 218. The adapter sleeve 103 that has internalthreads circumferentially is mounted on to the motor 101 via threadsafter sliding over the chuck 202. The adapter housing 104 is attached tothe pistol grip motor 101 sliding over the adapter sleeve 103 that hassix indentations 223 at about 60 degrees apart on its outer diameter toengage with adapter 104 with three threaded holes 224 at about 120degrees apart to accommodate three set screws. These set screws arealigned with the indentations on adapter sleeve 103 and can be tightenedso that the front subassembly (shown later in FIG. 3) can be adjustedand secured to rear subassembly (FIG. 2) to sui, e.g., an airplanestructure, and allow ease of handling for the mechanic so that thevacuum hose does not interfere with workpiece or other surroundingstructure. The holes 225 at about 180 degrees are provided to loosen theadapter 104 from its sleeve adapter 103. Adapter housing 104 also hastwo pins 226, (about 180 degrees apart) pressed fit into the outer bodydiameter of adapter 104. These pins 226 are used to engage the vacuumsleeve 206 for vacuum purposes. Once the adapter 104 is secured to themotor 101 via adapter sleeve 103, the position of chuck key access hole227 is such that chuck is exposed through hole 227 from where a chuckkey is inserted to attach spindle 218 to chuck 202. There are two O-ringgrooves 228 one on each side of hole 227 on the outer diameter ofadapter 104.

Two O-rings 205 are mounted in to the grooves 228 for sealing purposes.The vacuum sleeve 206 has two right angled cutouts 229 on the edge ofvacuum sleeve 206, about 180 degrees apart from each other and twoU-shaped cutouts 230 also 180 degrees apart, on the circumference of thea vacuum sleeve. The positioning of U-shaped cutouts 230 in relation toL-shaped cutouts 229 is such that when vacuum sleeve is aligned with thepins 226 on adapter and turned to the locked position, chuck key accesshole 227 is completely enclosed in vacuum sleeve 106 and the adapter 104is fully sealed. The vacuum sleeve 206 can be fully seated over theadapter housing 104 in sealed condition. A two piece split type rearmounting bracket 136 is mounted on to the front of the adapter 104 usingtwo screws. Two guide rods 138 are slid into two holes in bracket 136with flat end 137 into holes and clamped with two set screws. Theseguide rods 136 provide guidance to the front subassembly (FIG. 3)assembled with the rear subassembly (FIG. 2) that helps the frontassembly move in lateral direction without causing the subassemblies torotate with respect to each other. This completes the rear subassemblyas shown in FIG. 2.

Referring to FIG. 4, the front subassembly that is moveable in relationto rear subassembly, consists of a main body 212 on one side that facesthe countersink tool, and accepts the radial bearing 213 in to the borefor sliding fit and bronze collar stop 214. The spindle is then insertedfrom the right side (as shown) through the collar stop 214, through theradial bearing 213, and through the main body 212 until it stops againstthe collar stop 214. At that time, the dowel pin 215 is aligned with thehole in stop collar 214 and the hole in spindle 218 and pressed intocollar stop 214 and spindle 218 through the rectangular cutout 231 untilit is flush with collar stop on the opposite side. The rectangularcutout 231 is provided for allowing the pin 215 to be inserted into thecollar stop 214 and the spindle 218. Now the bronze bushing 211 is slidover the spindle 218 on the opposite end of the main body where thespindle is already protruding out through the main body 212. The spring210 is slid over the bronze bushing 211. The bronze bushing 211 insidediameter is made to slide fit over the spindle 218 and outside diameterof bushing 211 is made to slide inside the spring 210. This bushingprovides a support to the spring and guides it so the spring 210 doesnot buckle or bend during the countersink operation avoiding anyinterference between the any two wires of spring 210 and causing earlyfailure of the device or subassembly. It also provides a bearing surfaceto spindle 218. Then a radial bearing 209 is inserted on the spindle 218that is already protruding out of the main body 212, collar stop 208 isinserted on the spindle. The pin 207 is pressed into the hole throughthe U-shaped slots 232 of the main body 212, collar stop 208 andsimultaneously through the hole in spindle 218 after aligning the holesin collar stop 208 and spindle 218. The positioning of U-shaped slots232 are such that it provides space for pin 207 to be inserted, and allthese components are mounted on the spindle 218 in to the bore of themain body 212. In this case, collar stop 208 may require some force topush the radial bearing 209 into the open end of the main body until theholes in collar stop 208 and spindle 218 are aligned. Three ballplungers 235 are screwed into three tapped hole into the main body 212facing balls towards the rear side towards the motor 101 in such a waythat all three balls 242 that are part of ball plungers 235 are in oneplane perpendicular to the horizontal axis. The ball plungers 235 areadjusted to a preset tension. The countersink cutter 219 is screwed intothe spindle 218 and secured firmly as shown in FIG. 4. The guide plate216 is attached to the nose piece 217 using two dowel pins and with twoscrews for alignment. The ball plungers 235 that are adjusted to apreset tension in such a fashion, when subassembly of nose piece 217 andguide plate 216 is inserted into the main body 212 and turned, the nosepiece 217 and guide plate 216 subassembly snap into a locked position.

The locking action can take place because there are three small holes243 in the back side of guide plate 216. The three balls 242 snap intothree holes 243 in the back side of guide plate 216. There is also astop pin 244 in the back side of the guide plate 216. When the nosepiece 217 and guide plate 216 subassembly are turned for locking action,stop pin 244 provides the subassembly with a stop to avoid over travel.The nose piece 217 has three minuscule slots 460 near the front end.When a vacuum is applied at the time of countersinking operation, freshair is sucked through these minuscule slots 460 at high speed and itexpands inside the walls of nose piece 217 near the cutting edges of thecutter 219. The cool air hits the cutting edges of the cutter 219 thereby keeping the cutter cool during the cutting operation and extends thelife of the cutter. The nose piece 217 has a welded tubular attachment220 on the front side of the nose. This tubular attachment 220 acts asconduit for the dust or chips to be sucked out during the countersinkoperation. The open end of this tubular attachment 220 is attached toone end of vacuum hose 221 and the other end of vacuum hose 221 isattached to the exhaust end 245 of the motor 101. A breathable bag 159is attached to the exhaust end 245 of the vacuum device on motor 101 forcollection of dust or chips.

The speed control device 140 can be mounted into the front mountingbracket 139 such that the front part of the piston of speed controldevice 140 is slightly beyond the front surface 141 of the nose piece217 so as to provide a preloading effect on the piston before actualcountersink operation starts. The I.D ring 164 is slid on to the mainbody 212 and secured by nut 165 by screwing on the main body threads.This I.D. ring 164 identifies the size a complete assembly is designedfor, for a particular fastener used for assembly purposes. Now thisfront subassembly (FIG. 4) consisting of main body 212 assembled withits components in it along with front mounting bracket 139, guide plate216, nosepiece 217 with welded tubular attachment 220 and the vacuumhose 221 is ready to be installed in to the rear subassembly (FIG. 3)consisting of drill motor 101, adapter sleeve 103, adapter housing 104with O-rings 205, and vacuum sleeve 206 along with rear mounting bracket136 with guide rods 138.

The front subassembly (FIG. 4) can be installed in to the rearsubassembly (FIG. 3) by inserting front subassembly main body 212 intoadapter housing 104 and simultaneously the guide rods 138 inserted intoholes provided in front mounting bracket 139 and also inserting thespindle 218 into the chuck 102. At this time, the gage 222 is insertedin the slot 246 of the adapter 206 and the rear subassembly (FIG. 2) andthe front subassembly (FIG. 3) is pushed against the gage surface andheld tight. The chuck 202 is tightened with the chuck key accessingthrough the hole 227 of adapter housing 104. Once the chuck 202 istightened, the gage 222 is pulled out of the adapter 106 and stored awayand the complete assembly is ready for countersink operation.

Countersink Cutter and Spindle Assembly

FIG. 5 shows the assembly of the countersink cutter 219 with spindle218. The countersink cutter 219 can have a cutting edge 547 at about 100degree or about 130 degree which is an angle type of fastener used inaerospace industry or any other angle desired, and also has a pilot 548.The cutter 219 can have an outer body diameter knurled 558 so as to makeit convenient to engage and disengage the cutter with the spindle 18simply by holding the cutter 219 tightly by hand and turning itclockwise or counterclockwise as needed. The cutter 219 can have acylindrical body with an undercut 549 in such a location that the flutedarea 550 merges into this undercut 549. This arrangement can allowcomposite dust or chips to flow through easily from fluted area to theundercut 549. The outer cylindrical body of the cutter 219 has a hole551 to disengage the cutter 219, from the spindle 218 once it isassembled together.

The cutter shaft back end 565 can be flat and square in relation to thehorizontal axis of the cutter 219. The surface 565 seats against theflat surface 563 in the bore of the spindle 218. When the cutter 219with a square back end shaft surface 565 is assembled with spindle 218,the common contact surface 563 at the bottom of the bore of the spindleand 565 between the two becomes a reference surface for controlling thedepth of countersunk hole. This common surface between 563 and 565 canprovide the thrust in the direction of countersinking. The back end ofcutter 219 can have a reduced cylindrical diameter 552 with anothercylindrical groove 562 on the backend.

This groove is made to suit an O-ring 534 that when assembled withspindle 218 would keep the cutter tight inside the bore 553 of thespindle 218, and resist the tendency of becoming loose in the bore 553.The back end of the cutter 219 also can have a flat 554 that lets thecutter 219 pass past the spindle locking pin 533 on the side of thespindle 218. There is a partial grove or a flat 555 made on the back endwhere the locking action between the spindle 218 and the cutter 219takes place. This condition provides the torque for the cuttingoperation. The spindle 218 has a counterbore 553 on the front end (thesame bore diameter 553 depending) on the shaft design to accept theshaft end of the cutter 219. There is a locking pin 533 across thecylindrical body diameter that is offset from the center of the spindle218. At the bottom of the cylindrical bore 553, a small hole 561 isprovided so that when cutter 219 along with O-ring 534 seated in to thegroove 562 of cutter 219 is mounted into the bore 553, the air trappedin the space in bore is pushed out at the bottom and also to help removethe cutter 219 out of the cylindrical bore 553 since the pressure atboth ends of the back end shaft and the front outside the bore 553 isabout the same.

There can be another hole 555 that intersects the small hole 561. Hole551 may help remove the cutter 219 out the spindle 218 by placing a pinthrough it and turning the cutter 219 counterclockwise and sliding outof the spindle 218. The back end of the spindle 218 has three flats 564with knurls on them placed at about 120 degree apart so that the chuck102 jaws can grab on these flats 564. These knurls on the flats 564provide resistance to avoid slippage between the jaws of the chuck 202and flats 564 during the countersink operation. The back mountingcylindrical surface of the reduced diameter 552 of the cutter slipssmoothly into the counterbore 553 of the spindle keeping the cuttersymmetrical around the horizontal axis and concentric to the spindle 218and the O-ring 534 provides slight interference between the bore 553diameter of the spindle 218 and the O-ring 534.

Operational Technique

In use and application, a tool is designed to configure a predeterminedhole profile in a machining operation to facilitate particularapplications. The operator turns the motor on and aligns the pilot ofthe countersink cutter with the hole to be countersunk and inserts thepower tool assembly and pushes the whole device until the main bodybottoms out at the back end against the adapter where the gage has beenused for setting up the tool. Once the tool has bottomed out, he removesthe motor and works on the next hole. The hole can be countersunk to adesired depth that the tool has been set up for.

In one embodiment, a predetermined configuration hole profile can beprepared in a quick and efficient manner. The cutting or boring actionof a drilling tool may be performed by the drilling tool, such as acombination of a tool holder and a drill insert attached thereto.Typically the cutter engages the material to be cut upon relativerotation between the tool and work piece.

Cutter Replacement in Assembly

The process of replacing the cutter 219 from the spindle 218 during thecountersink operation involves holding the motor assembly in one hand,then first remove the hose 221 from the tubular attachment 220 of thenose piece 217 and using second hand the removal of subassembly of theguide plate 216 and the nose piece 217 by turning counterclockwise andsliding it out of the main body 212. The cutter 219 is exposed out ofthe front subassembly FIG. 3. A pin is inserted into the hole 555 of thespindle 218 holding it tight, and the cutter 219, while holding on theouter body, is turned counterclockwise and pulled out of the bore 553 ofthe spindle 218. If the cutter 219 cannot be turned by hand for removalpurposes, another pin is inserted in hole 551 of the cutter 219, andturned counterclockwise while holding the pin inserted in hole 555providing a torque to loosen the cutter and then pulled out of the bore553 of the spindle 218. Once the cutter 219 is removed from spindle 218,a new cutter is slid in to the bore 553 of the spindle 218 past the pin533 until it bottoms out at the top of spindle 218 and then turnedclockwise until it stops. The cutter 219 is in locked position and thesubassembly of the guide plate 216 and the nose piece 217 is locked intoposition by inserting into the main body 212 and turningcounterclockwise until it stops against the stop pin 244 of the guideplate 16. The hose 221 is connected to the tubular end 220 of the nosepiece 217. The motor assembly is ready to be used again for countersinkoperation.

This magnetic design can be more suitable for composite and othernon-metallic materials. One embodiment is countersink process and methodfor replacing a cutter using an assembly tool process to replace cutterwithout any consequential result of corrective action after completionof countersink operation. In one embodiment, the process ofcountersinking includes creating a countersunk hole by using the devicedesigned for this purpose. More particularly, this embodiment can makeuse of the concept that the travel of spindle can be controlled bypreset gaged distance prior to the countersink operation. The frontsubassembly can travels back laterally against the fixed rearsubassembly without any rotational bodies touching each other.

Other Embodiments

In one embodiment, the cutter is made such that the relative distancebetween the intersection of the longitudinal axis and the cutting edges,when projected on to the longitudinal axis and the squared back end ofthe countersink cutter, is maintained accurately so that when cutter isreplaced the cutting edges always fall at the same location in the toolassembly.

In another embodiment, the cutter's shaft back end can be at 90 degreeswith respect to the longitudinal axis and is perfectly squared. Thissurface can be used as a reference surface for maintaining the length ofcutter from the intersection of projecting the cutting surface andhorizontal axis and the back end of the shaft for replacement purposes.The cutter's outer body diameter also has a squared back end and when itis assembled it has a little clearance between the spindle and the backend of the cutter body diameter.

In another embodiment, the relative distance between the front face ofthe nose piece of the front part of assembly and the front surface ofthe spindle is always the same.

In another embodiment, the cutter can be positioned such that theintersection of pilot's outer diametrical surface and the cutting edgeof the countersink is in line with the front surface of the nose pieceof the front part of assembly, when the motor is at rest and is not inuse and it has not been set for any depth of cut, i.e., the back end ofthe main body and the front end of the adapter mounted on the pistolgrip motor, touch each other and indicate that the reading of thecountersink gage would be at zero or it also indicates that cutter'sintersection of pilot's outer diametrical surface and the cutting edgeof the countersink is on the same plane with the front part of toolassembly.

In another embodiment there can be threads on the back end of cutter andthe spindle as normally done on standard cutters.

In another embodiment, the knurling can be on the outer body diameter ofthe cutter so as to engage and disengage cutter by holding the cuttertight by hand and turning it clockwise and counterclockwise to achievethe desire effect.

In another embodiment, a gaging system sets up the depth of countersinkby use of flat gage through the tool assembly and still getting the sameresults even when cutter is changed.

In another embodiment, the complete tool assembly with motor setup canbe placed on work bench. There is less danger of getting the cutterdamaged even during the idle times. This feature comes in very handyespecially in the light of cutters that are manufactured with diamondblades bonded to it at the flutes since the diamond cutters are veryexpensive.

In another embodiment, the tool has small restrictions provided in frontof the tool assembly where the cutting edges of the cutter are. At theserestrictions, ambient air is sucked into the nose piece of the toolassembly. The sucking action of fresh air creates a void with strongnegative pressure around these restrictions on the opposite sides of thewalls where these restrictions are provided. The sucking action causesthe ambient air to expand near the area of restrictions, That is theplace where the cutting edges of the cutter are, where the expansion ofair takes place. This expansion of air causes the temperature to drop inthe vicinity of the cutter cutting edges during the chip formationaction or dust formation action due to the grinding of cutting edgesagainst the abrasive composite surface. So, the cutter remains coolduring cutting action.

In another embodiment, the chip breaker feature is provided on all edgesstaggered from previous cutting edges except the last cutting edge ofthe cutter. The cutting edge finally sweeps the countersunk surfacegiving a fine finish to the conical surface of the hole.

In another embodiment, the engage and disengagement of cutter withspindle is made easier by providing the outer body diameter that hasknurls on it for holding the cutter tight during assembly ordisassembly.

In another embodiment, a vacuum at the nose piece can be included at thefront part of the assembly. The pistol grip motor used has its ownvacuum generating feature, but this is not enough when it is connectedto tool assembly. Plenty of air is being sucked through the top part oftool assembly dissipating and leaking away through other areas of toolassembly and making the vacuum process ineffective. So in accordancewith this embodiment, provision is made by sealing the openings at thetop part of tool assembly by use of O-rings and a vacuum sleeve thatseals the opening at the top part of tool assembly.

In another embodiment, the provision of two pins diametrically oppositeto each other on top of adapter to engage the vacuum sleeve for vacuumpurposes and sealing the assembly. “L” shaped cutouts are provided andare at a slight angle to let vacuum sleeve engage with pins tightly andkeep the sleeve locked until it is removed when needed.

In another embodiment, a method of collection of debris, such ascomposite dust or metallic chips in to the breathable bags. An externalplant vacuum or accessory vacuum hose can also be connected to thissystem to increase the effectiveness of the vacuum system in place ofbagging system.

In another embodiment, a feed control for countersinking process isprovided in the tool assembly by use of feed control device. This devicetakes over the operator's speed of countersinking process providingbetter countersunk surface quality and increases the life of cutter.

In another embodiment, the lateral movement of the front subassembly andthe rear subassembly is guided by guide rods for smooth operation.

In another embodiment, window openings are provided in the adapter andmain body of the tool assembly to access the roll pins for disassembly,if needed, that keep this device fastened together to each other.

In another embodiment, there is provided a tool assembly that mainlyconsists of two sub-assemblies—the front subassembly that moves alongthe longitudinal axis when the complete assembly is intact where as therear subassembly that as stationary subassembly remains fastened to thedrill motor held in hand when in use. The rear subassembly that issecured to the power drill motor mounted with a chuck or similarcolleting device to secure spindle, a countersink bit attached to thespindle enclosed in a cylindrical part of the nose piece that has avacuum tube welded to it, a vacuum hose—one end is attached to this exitend of the nose piece and the second end of the vacuum hose is attachedto the exhaust end of the pistol grip motor.

In another embodiment, the rear subassembly part of the completeassembly consists of a pneumatically driven power drill motor, which hasan adapter sleeve mounted on it using internal screw threads on adaptersleeve and outside diameter of this sleeve has six indentations 60degree apart and at a fixed distance from the front edge to accommodatethree set screws to secure an adapter housing for the assembly. Theoutside diameter of adapter sleeve is concentric with the drill motorthreads to minimize any misalignment when an adapter is slipped on theoutside diameter of adapter sleeve. The adapter housing inside diameteris made to slip fit on the adapter sleeve outside diameter. This adapterhousing has three threaded holes 120 degrees apart on its outer diameterat exact distance from edge to align with three indentations on adaptersleeve and provided to secure adapter housing on the adapter sleeve. Thesix holes provided on adapter sleeve provide rotational positionvariations to the adapter housing so the operator can align the frontsubassembly with the rest of work piece and surroundings. This adapterhousing also has another two holes offset from previous three threadedholes. These holes are provided to engage or disengage adapter housingfrom adapter sleeve. Along with above features of adapter housing, twogrooves are provided on the outside diameter of housing some distanceapart. In between these two grooves two large diameter holes 180 degreeapart are provided perpendicular to the longitudinal axis. These holesare provided to accommodate a chuck key for tightening the spindle andtwo grooves are provided to accommodate two O-rings. These O-rings arefurnished so that when a vacuum sleeve is slipped on the adapter housingover these O-rings, vacuum sleeve provides means for sealing thiscaptured area between O-rings. Also another feature of this adapterhousing is there is a provision of gage port so that a flat gage can beinserted through this for setting up the depth of countersink. Thepositioning of the two big opening in the adapter housing is such thatchuck which is used for securing spindle is accessible through it sothat a chuck key can be inserted for securing spindle.

In another embodiment, the adapter housing can have two small holesprovided on the circumference of the outer diameter that accommodatestwo dowel pins located 180 degrees apart. These dowel pins are press fitin to these holes. The purpose of the dowel pins is to engage anddisengage the vacuum sleeve when it is slipped on the adapter housing.After engaging these pins with two right angled cut outs 180 degreesapart made on the vacuum sleeve, the vacuum sleeve can then be locked tothe adapter housing by turning the vacuum sleeve until it stops. Thepositions of the tracks or right angled cutouts on vacuum sleeve are insuch a relation with the two dowel pins, that when sleeve is locked onthe adapter housing, the two big openings for chuck key are enclosedtotally inside the vacuum sleeve between two O-rings. This creates acompletely sealed area to make vacuum action effective. Another featureof vacuum sleeve is that it has two u-shaped long slotted cutouts on itsbody in such a relationship with right angled cutout for dowel pins thatwhen it is in disengagement position from adapter housing, the twoopening for chuck insertion are exposed so that chuck key can be used todisengage the spindle for adjustment purposes. The u-shaped design alsohas another advantage that it provides access for the gage to beinserted in to the gage port for setting up the complete assembly forcountersink process. The gage port that is provided on the sleevehousing is aligned with the u-shaped opening in the vacuum sleeve andgage is inserted to make the complete setup ready for operation. Whilethe countersink operation goes on and when the vacuum sleeve is inlocked position, the gage port is then covered under the vacuum sleevewhere there in no u-shaped opening. This prevents the dust or debris toget into gage port and keeps it clean. Another feature of thisembodiment is that a provision is made so that the back end of the gageport surface facing towards the motor provides the stop surface for themain body indicating completion of countersink depth desired. When nogage is inserted into the gage port and the back end of the main bodytouches the surface of the adapter house, this indicates zero setting ofthe cutter. The adapter housing also has a hole through its body in thecenter in longitudinal direction to accept the spindle.

In another embodiment, the adapter housing can have an inside diameterat the front of the adapter housing that provides the guidance to thefront subassembly during the assembly of front subassembly to the rearsubassembly. It is aligned so that rear subassembly provides the frontsubassembly the freedom to slide in and out of the rear subassemblyduring the countersink operation.

In another embodiment, the means for attaching the front subassembly tothe rear subassembly include the drill motor comprises a main body thathas back end such that it slides into the front end of the adapterhousing of the rear subassembly. The back end of the main body also hasfour slotted openings. The purpose of these openings is to provideaccess to the roll pin that is pressed tightly into the diameter of thespindle crosswise to hold other components inside the main body, such asbronze bushings, radial bearing, spring etc. The access is provided sothat front subassembly can be dismantled conveniently using a small handpunch manually. Another feature is the provision of a compression springthat helps bring the front assembly to the original position. Anotherfeature of the main body is that it has three alignment lobes built onit. These provide the means for alignment with the nose piece that isdetachable from the front subassembly for the purpose of replacement ofcutter. Another advantage of these lobes is that these provide room forinstallation of three ball plungers. These ball plungers are the meansfor securing the nose piece to the main body via a guide plate inbetween. The lobes are the integral part of the main body but can bemade as a separate part slip fitted on to the main body and held withset screws. This may provide a means to cut manufacturing cost. Anotherfeature of the main body is the positioning of three lobes that providedonly one way for insertion of main body into the nose piece via guideplate causing no confusion to operator as to how to locate lobes inrelation to lobe opening provided in the guide plate. The front part ofthe main body has four longitudinal slots that provide access to theroll pin that holds the shaft assembly together along with bearinginside the main body and bronze bushing. The front end of the main bodyalso has a precision bore to accommodate a radial bearing that supportsthe spindle in the front assembly. The feature is depicted as a completefront sub assembly is held together by these two roll pins that areprovided on two ends of the spindle. In between the two roll pins arebushings and bearings and spring. The radial bearings provided on bothends of the main body provide smooth rotational movement of spindle,remove misalignments in the front sub assembly and provided radialsupport; bronze bushings provide support to radial bearings and smoothoperation of spindle.

In another embodiment, the main body can have an identification bandthat is slipped on to outside diameter and then secured with aidentification band retainer. This identification band provides themeans of identifying what size fastener the setup is made for. Differentcolors are used to depict various sizes of holes diameter setup.

In another embodiment, the front subassembly is that a guide plate withspecial designed openings is provided to accommodate the lobes of themain body. The guide plate allows the alignment between the two partsand there is provided a stop pin on the underside of the guide plate.This stop pin acts as a stop to prevent the main body for over travelinginside the nose piece when main body is engaged with nose piece. Onemore feature provided in the guide plate is that it has three smalldiameter holes for the ball plungers to rest when main body is securedto the nose piece. There, also are two male dowel pins pressed in theunderside of the guide plate so that guide plate can be aligned with thenose piece and then secured with flat head screws.

In another embodiment, the front subassembly also comprises of the nosepiece as has been mentioned earlier. This nose piece has its own tubularweldments welded to the side for debris to be evacuated before it getsinto the rest of mechanism. This tubular weldment is connected to oneend of vacuum hose to carry all the debris out to a means of collectionof debris, such as breathable bag. The second end is then connected tothe exhaust end of the motor where debris collection bag is attached.The nose piece has another feature at the front end that it is providedwith three minuscule sized slots-near the front end where the cuttingedges are when cutter is in place. These slots act as cooling devices.When vacuum is applied during the cutting action, fresh air at ambienttemperature is sucked in from these tiny slots. Air expands inside thewalls of nose piece in and along the cutting edges of the cutter thisexpansion of air drops the temperature of the cutter when air hits onthe cutting edges. This keeps the cutter cool and extends the life ofcutter several times comparing to action where the situation when thereis no cooling.

In another embodiment, the nose piece has is that there is provision forcutout in the front of nosepiece so that the operator can see thecountersink bit, otherwise the outside diameter of the nose piece wouldblock the sight and would not be easily able to insert the cutter tip into the existing hole. This nose piece also has a bore drilled in to itto precisely accommodate the main body front end.

In another embodiment, the front part of subassembly is that a spindleand the cutter have a quick change mechanism for securing purposes. Thespindle has a precision bore so that the cutter precision ground shaftdiameter can slip into the bore providing the alignment between thespindle and the cutter with minimal radial play allowed depending uponthe standard manufacturing practices. The spindle has a cross mountedpin inside slightly offset from the center of the spindle, so that thecutter can be inserted through one end past the pin and the cutter alsohas a flat at the shaft end to get past the pin. The cutter also hasanother feature, ground flats besides the previously mentioned flat onthe shaft that can trap the pin in the spindle when the cutter is turnedabout thirty degrees. The tolerances are so close that there is nolateral play or radial play, there by securing the cutter in thespindle. The pin acts a driving member of the spindle when it trapped inbetween flats of the cutter. Another feature that is provided on theshaft end is that it has a groove to accommodate an O-ring on it. ThisO-ring on the shaft end, when it is inserted into the spindle bore, itkeeps the cutter in place without any fear of losing the cutter if themotor is turned counterclockwise or otherwise cutter may slide out ofspindle. Unless the operator decides to take out the cutter it would notcome out because of sufficient resistance O-ring provides between thecutter and the spindle.

In another embodiment, there are two brackets mounted on the completeassembly, one bracket is secured to the main body of the frontsubassembly and the other bracket is secured to the fixed end of rearsubassembly using socket head cap screws. These brackets are thenmounted with two guide rods that are secured on the rear bracket on oneend using set screws and slide back and forth on the other ends of guiderods in precision holes provided in the front bracket. These guide rodsprovide stability to the whole setup and allows smooth sliding operationeven though the main body has its own feature that slides inside theadapter housing. The front bracket also has another feature toaccommodate a speed control and shock absorber device mounted of thefront end. This device provides support and resistance that isadjustable on it, to the operator when he pushes the motor against theairplane structure or panel to countersink holes. The operator canadjust this resistance so it is not over bearing yet not be able toplunge the countersink tool in to the panel causing the damage to it.Speed control device may also include a pressure control knob that maybe rotated to control the tension setting of surge control device, or inother words, to control the axial force required to move plungerrelative to hydraulic cylinder. Increasing the tension setting of surgecontrol device provides greater resistance against an axial forceapplied to countersink, and thus decreases the axial speed, or feed, atwhich countersink tool may travel during countersink operation.Likewise, decreasing the tension setting provides less resistance andincreases the axial speed at which countersink may travel. The surgecontrol tension setting may be selected based on one or more criteria,such as for example, the material properties and dimensions of theworkpiece, the material properties and dimensions of countersink tool.It should be understood that surge control device may include additionalhydraulic dampers or any other suitable means of controlling the axialspeed, or feed, of cutting tool, such as, for example, springs orcompressible materials.

In another embodiment, several component parts are designed in such away these can be manufactured very economically or some even purchasedof the shelf to make a complete assembly. The countersink cutter isspecially made from materials that would be more suitable forapplication where it is going to be used on, for example, for compositematerial to be cut, the countersink material used on cutting edges isfine grade diamond blades, and for tough materials, the cutter is madefrom tungsten or molybdenum carbide. This carbide cutter can also beused on aluminum materials. Even high speed steel can be used for cutterfor aluminum applications. But the most important part of the cutter isthat it must be made extremely accurate with tight tolerances to achievethe correct results and make the power tool countersink assembly errorproof.

From one perspective, a basic principle of setting up the tooling with aflat gage between the front and the rear assemblies and method ofengaging and disengaging the front nose piece with main body can beutilized also right angle motors, in stationary machine tools to achievethe depth control of the drilling or countersinking operation or similaroperation where a rotary cutting tool with a pilot or without a pilot isutilized. The cutter shaft design feature can also be made acceptable toother rotary tools such as drill and countersink combination tools,drills, counterbores etc. It is understood that the tool can also beused in other industries beside aerospace industry where accurate andcontrolled depth of countersink is needed.

The above detailed description of the embodiments, and the examples, arefor illustrative purposes only and are not intended to limit the scopeand spirit of the invention, and its equivalents, as defined by theappended claims. One skilled in the art will recognize that manyvariations can be made to the invention disclosed in this specificationwithout departing from the scope and spirit of the invention.

What is claimed is:
 1. A countersink assembly adapted to be attached toa drill motor for drilling and countersinking a hole in a workpiece,comprising: an approximately cylindrical rear subassembly extendingbetween a first end and a second opposed end and having a slot for agage, wherein the outer diameter of the assembly defines an approximatefirst cylinder, the rear subassembly is mounted to a drill motor with anadaptor sleeve; an approximate first cylindrical body has a through holefor providing access to a chuck for tightening purposes and has twoO-ring grooves where two O-rings are mounted on; said rear subassemblyalso comprises of a cylindrical vacuum sleeve that slides over the firstcylindrical body with the O-rings mounted on it; an approximate cylinderfront assembly having a main body, a coaxial spindle with a spindleshaft, wherein the front subassembly moves laterally in relation to saidrear subassembly; the front subassembly also comprises of a spring witha bushing inside it entrapped in said main body; having quick changemechanism for removal of a nosepiece subassembly; and said nosepiececonnected to countersink assembly vacuum system of a motor or connectedto external source; an approximately cylindrical countersink cutter,operably connected to said drill motor, said coaxial spindle having apin (533) inserted in a bore to accommodate a cutter shaft using a quickchange mechanism to engage, having a body diameter with knurls and ahole (551) through, a pilot (548) and a set of cutting edges, whereinsaid rear subassembly is stationary; said coaxial spindle shaft mountsinto said drill motor; said cutter shaft has a flat front end surface oredge (556) and a flat back end (565) along a longitudinal axis, anangular flat surface, and has a groove (562) to accommodate an O-ring(534); said front end surface or edge (556) of said cutter shaftcoincides with a back end of said body diameter (558) of said cutter;said body diameter (558) has said knurls on a cylindrical body diametersurface; an angular flat surface locks into said pin of said coaxialspindle; and an intersection point (566) of the longitudinal axis andsaid cutting edges, when projected on to the longitudinal axis, is heldin alignment at a substantially constant distance from the back end(565) surface of said cutter; and the distance between a front surface(557) of said coaxial spindle and the front surface (141) of said nosepiece is constant and is equal to the distance between said front endsurface or edge (556) of body diameter (558) flat surface and the center(567) of the radius when drawn between the tangent of said pilotdiameter and said cutting edges; a subassembly consisting of a rearbracket (136) mounted on said stationary first cylindrical body,connected with an alignment rod (138) with screws to a front bracket(139) mounted on said main body; a speed controller (140) adjusted to beused as a stop mounted on said front bracket facing towards said rearbracket, said gage is used between said speed controller and said rearbracket for setting up the depth.
 2. The assembly as claimed in claim 1,wherein the back surface (565) of said cutter bottoms out at the bottom(563) of said coaxial spindle bore when assembled.
 3. The assembly asclaimed in claim 1, further comprising of an O-ring (534) on said cuttershaft; when assembled into said bore (553) of said coaxial spindle,provides resistance between said cutter shaft and said coaxial spindlebore and helps said cutter remain in place and concentric with saidcoaxial spindle.
 4. The assembly as claimed in claim 1, furthercomprising outside major diameter (558) having said knurls and said hole(551) through said body diameter of said cutter that engages saidcoaxial spindle.
 5. The assembly as claimed in claim 1, wherein saidangular flat on said cutter shaft and said pin are inserted at an offsetposition from center through said bore of said coaxial spindle andengage each other to create a quick change mechanism for said cutter tobe mounted and removed from said coaxial spindle and provide torque tosaid cutter.
 6. The assembly as claimed in claim 1, wherein said coaxialspindle has said bore to be able to accommodate said cutter shaft endwith minimum play between said cutter shaft and said coaxial spindlebore.
 7. The assembly as claimed in claim 1, wherein said coaxialspindle has said bore to be able accommodate said O-ring mounted on saidcutter shaft.
 8. The coaxial spindle as claimed in claim 1, wherein saidcoaxial spindle shaft has one or more flats with serrations or saidknurls to provide slip resistance when external forces are appliedduring countersink operation.
 9. The assembly as claimed in claim 1,wherein said front subassembly has a quick change mechanism to allow forthe removal and assembling of said nose piece subassembly; and to allowfor the exposure of the cutter for replacement purposes.
 10. Theassembly as claimed in claim 1, wherein the main body has multiple lobes(234) at equally spaced number of degrees apart and has at least samenumber of ball-plungers mounted in as many number of lobes, preset to acorrect tension to allow for quick engagement and disengagement fromsaid nosepiece mounted with a guide plate with cutouts, one less numberof cutout compared to number of lobes in said main body, and a v-shapedopening (235) for viewing said cutter pilot and to maintainconcentricity between the front and back subassemblies guided bydiameter (233) of the main body (212) where the cutouts are present. 11.The cutter assembly as claimed in claim 1, wherein said nose piece hasseveral minuscule openings such as holes or slots (460) to make vacuumaction more effective and keep said cutter cool when the air expands atthe entrance dropping air temperature substantially and cooling saidcutting edges entrapped inside said nosepiece and workpiece space. 12.The assembly as claimed in claim 1, wherein the main body has multiplelobes that pass through cutouts, one less number of cutouts in saidguide plate, compared to number of lobes, and a v-shaped opening in saidsubassembly of said guide plate and said nose piece that acts as a guidefor lobes on said main body; and said nosepiece is turnedcircumferentially for locking purposes, such that all ball plungers snapinto corresponding holes on the back side of said guide plate and saidmain body stops from further movement and locks itself with said nosepiece.
 13. The assembly as claimed in claim 1, wherein said gage isinserted through said slot in rear subassembly touching the surface ofadapter housing (104); and said front subassembly slides towards saidrear subassembly until said main body as part of said front subassemblytouches said gage; and said coaxial spindle shaft, that is a part ofsaid front subassembly, is secured into chuck with the aid of chuck key,and said bushing (211) length is adjusted to avoid over travel.
 14. Theassembly as claimed in claim 1, wherein said speed controller is used asa stop and is mounted on said front bracket, facing backwards towardsaid rear bracket where said gage is used between said speed controllerand said rear bracket to set a gage depth.
 15. An approximatelycylindrical cutter operatively connectable to a coaxial spindle and adrill motor, compromising: a set of cutting edges and a cutter shaft,wherein said cutter shaft has a flat front end surface or edge (556) anda flat back end (565) along a longitudinal axis, an angular flatsurface, and a groove (562) that accommodates an O-ring (534); saidfront end of the shaft coincides with the back end of the body diameter(558) of said cutter; said angular flat surface locks into a pin of saidcoaxial spindle; and an intersection point (566) of the longitudinalaxis and said cutting edges, when projected on to the longitudinal axis,is held at a constant distance from said back end (565) surface of saidcutter; and said cutter is operatively connected to said spindle andsaid drill motor through said coaxial spindle shaft; wherein thedistance between a front surface (557) of said coaxial spindle and afront surface (141) of a nose piece is held constant and is equal to thedistance between said front end flat surface or edge (556) of said bodydiameter (558) and a center point (567) of the radius when drawn betweenthe tangent of said pilot diameter and said cutting edges of saidcutter; and an intersection point (566) of the longitudinal axis andsaid cutting edges, when projected on to the longitudinal axis, is heldat a constant distance from said back end (565) surface of the cutterand is equal to the distance from the surface (563) of said coaxialspindle bore and said front surface (141) of said nose piece and addingthe distance between said intersection point (566) and said center point(567) along the axis.
 16. The cutter as claimed in claim 15, whereinsaid coaxial spindle shaft has one or multiple flats with serrations orknurls to provide slip resistance when external forces are appliedduring countersink operation.
 17. The cutter as claimed in claim 15,wherein the cutter has number of flutes for said cutting edges for chipsto flow through, in such a fashion that all flutes merge into a circularannular opening space (568) in the back which facilitates collection ofdust or chips to be vacuumed through said nosepiece, thereby keeping thecomplete assembly of countersink tool free of debris.